1. Field of the Invention
The present invention is directed to a spectrally efficient, point to multi-point communication system having one or more base stations and a number of system subscriber stations.
2. Discussion of the Known Art
A wireless local loop system known as xe2x80x9cAirLoopxe2x80x9d is available from the assignee of the present invention. The AirLoop system operates to connect, for example, telephone central switching sites to homes or businesses using fixed wireless equipment, instead of conventional copper wire pairs or xe2x80x9cloopsxe2x80x9d. Thus, subscribers within a coverage area of a system base station may enjoy the same features and services offered by existing wired local loop systems, for example, plain old telephone service (POTS) to ISDN.
U.S. Pat. No. 5,448,753 (Sep. 5, 1995) discloses a wide area radio communication system in which central stations direct narrow antenna beams over sub-service areas, to communicate with peripheral stations in such areas during coordinated time intervals.
According to the invention, a base station having a defined geographic coverage area in a wireless communication system, includes a base receiver, a base transmitter, and a base antenna array coupled to the base receiver and the base transmitter. A base station processor is configured to exchange control and data signals with operating components of the base station. The antenna array is constructed and arranged to operate in a first mode wherein the array steers a narrow antenna beam in the direction of a subscriber station in the coverage area of the base station, for transmitting first downlink signals to the subscriber station and for receiving first uplink signals from the subscriber station, and a second mode wherein the array defines a wide beam for transmitting second downlink signals simultaneously to a number of subscriber stations in the coverage area and for receiving second uplink signals from the subscriber stations.
According to another aspect of the invention, a subscriber station for deployment in a wireless communication system, includes a subscriber receiver, a subscriber transmitter, and a subscriber antenna coupled to the subscriber receiver and the subscriber transmitter. A subscriber station processor is configured to exchange control and data signals with operating components of the subscriber station. The subscriber station transmitter is constructed and arranged to modulate data on a selected number of carriers which carriers are spaced spectrally from one another, to produce simultaneously a corresponding number of first uplink signals for reception at a system base station having a coverage area in which the subscriber station is located. The number of carriers selected for transmission is a function of a rate at which a user desires to transmit data from the subscriber station to the base station.
For a better understanding of the invention, reference is made to the following description taken in conjunction with the accompanying drawing and the appended claims.